If you utilize flaik's Bookings functionality and want to learn more about the applicable configuration required in RTP, check out the Bookings - RTP settings section of the Knowledge Base to learn more about everything that needs to be taken care of before lessons can be sold via Bookings.
Quick Overview
Required configuration for lesson products used in Bookings:
Sale Location - Bookings requires a unique Sale/Audit location
Components - currently Bookings only supports components that have a component type of Private or General
Sales Channels - only relevant for Bookings resorts
GL Account - specific clearing account for Bookings transactions
Payment method - specific for Bookings transactions